An Amazing Sight: The Mussels of Muir Beach, California
I never imagined what I saw on the California coast.
No, it’s not a typo. While there might be some muscles to be seen on Muir Beach the extraordinary sight that awaits you there are the California Mussels (Mytilus californianus).
These shellfish can be found from the Baja Peninsula up the California coast to the Aleutian Islands.
Mussels are bivalves that attach themselves to rocky surfaces with strong thread-like fibers. They like to be in an area where the surf rushes over the rocks, as they are filter feeders and collect plankton from the water moving with the tides.
The California coast is rocky. The surf is strong. And the mussels hang on without difficulty! It is amazing. The mussels form large colonies and often form layers by attaching as well as the rocks.
Mussels can live for twenty years or more. But, as filter feeders, they are susceptible to changes in water quality. This, in turn, affects the living organisms that feed on the mussels, including humans.
If pollutants enter the water, and the mussels filter that water, the pollutants (poisons or toxins — whatever you want to call them) end up in the mussel and whatever else eats the mussels.
Last June, we saw a large concentration of them just North of San Francisco on Muir Beach when we vacationed in Northern California.
Thousands of mussels, of various sizes could be seen clinging to the large rocks on the beach near where the surf breaks. Seriously, they were everywhere.
The tide was out; therefore we could walk around the rocks on the beach and get a good look at the mussels. It was cool, but also kind of otherworldly.
Amongst the mussels were barnacles, also stuck to the rocks, starfish in the tide pools at the base of the rocks, along with these gross-looking but interesting things called sea anemones. Occasionally, a crab could be seen scooting for cover or a small fish darting around in the shallow seawater.
But the most noticeable of all were the mussels clinging to the rocks. Thousands of mussels. Everywhere you looked.
We made plans to go to the Pelican Inn for lunch. Prominently featured on their menu was — you guessed it — mussels! Now, I’ve eaten mussels before, but after seeing them on Muir Beach clinging to rocks for their dear little lives, I think it will be a long time before I eat mussels again.
It is highly discouraged to collect wild mussels to eat due to the inability to determine if toxins are present. There are regular warnings ( 2023, 2022, 2021…) against the collection of this shellfish for consumption. Restaurants, on the other hand, will have mussels available as determined by the local health codes and warnings, if caught commercially.
Regardless, having an up-close look at the mussels in their natural environment was amazing and something I’ll remember for a long time to come!
The following references were used in creating this article:
https://thewatershedproject.org/whats-in-your-watershed-california-mussels/
https://oceanconservancy.org/wildlife-factsheet/mussel/
